8V79S680 Datasheet | Renesas

Description The 8V79S680 is a fully integrated, clock and SYSREF signal fanout buffer for JESD204B applications. It is designed as a high-performance clock and converter synchronization solution for wireless base station radio equipment boards with JESD204B subclass 0, 1, and 2 pliance. The main function of the device is the distribution and fanout of high-frequency clocks and low-frequency system reference signals generated by a JESB204B clock generator such as the IDT 8V19N480, extending its fanout capabilities and providing additional phase-delay. The 8V79S680 is optimized to deliver very low phase noise clocks and precise, phase-adjustable SYSREF synchronization signals as required in GSM, WCDMA, LTE, LTE-A radio board implementations. Low-skew outputs, low device-to-device skew characteristics and fast output rise/fall times help the system design to achieve deterministic clock and SYSREF phase relationship across devices. The device distributes the input clock (CLK) and JESD204B SYSREF signals (REF) to four fanout channels. In each channel, both input clock and SYSREF signals are fanned-out to multiple clock (QCLK) and SYSREF (QREF) outputs. Clock signals can be frequency-divided in each channel. Configurable phase-delay circuits are available for both clock and SYSREF signals. The propagation delays in all signal paths are fully deterministic to support fixed phase relationships between clock and SYSREF signals within one device. Clock divider can be bypassed for low-latency clock paths. The device facilitates synchronization between frequency dividers within the device and across multiple devices, removing phase ambiguity introduced in dividers between power and configuration cycles. Each channel supports clock frequencies up to 3GHz. In an alternative configuration, for instance JESD204B subclass 0 and 2, the SYSREF (QREF) outputs can be configured as regular clock outputs adding additional clock fanout to the device. All outputs are very flexible in...